1. Field of the Invention
The present invention relates generally to organosilicon pastes having improved resistance to sunlight, a process for the preparation thereof, and the use of such pastes for the protection of electrical insulators. More particularly, the present invention relates to organosilicon pastes having inorganic fillers and additions of ultraviolet radiation absorption effective organic compounds.
2. Description of the Prior Art
In the distribution of high voltage electric current, it has been observed that insulators for the high voltage lines commonly become covered with various foreign materials, predominantly thin coatings consisting of agglomerated dust. Such a coating, upon interaction with the ambient, frequently proves to be an electrical conductor due to absorption of water and the like. This often results in arcing and tracking of electric current which may frequently be fatal to the integrity of the distribution system.
It is known that these problems may be relieved, in part, by depositing thin layers of organosilicon pastes on the insulator. Subsequently, dust which then coats this surface will itself be coated by the paste substance through an exudation effect, with a concomitant diminution in the tendency for this dust or foreign material to become an electrical conductor. Significantly, however, the known organosilicon pastes have a propensity to transform into a rubbery or elastic mass upon exposure to sunlight. Initially, a skin is observed to form on these known pastes when exposed to sunlight followed, ultimately, by complete conversion of the mass to a rubbery material which tends to crack in this aged condition. Once this occurs, the paste no longer is efficacious for its desired application and deterioration of the insulators may then proceed as if the paste were not present.
Accordingly, the need exists to provide a paste for the coating of electrical insulators, particularly those used in connection with high voltage electric current, which do not suffer the significant deficiency of aging in the presence of sunlight or other sources of ultraviolet radiation. Likewise, the need exists to provide a method for simply, efficiently, and economically manufacturing such desirable products.